Use the Tone Scales section of the Plate Control Strip to view the effect of the tone curve applied to the job. The tone scales make it easy to visually check the applied tone curve or to check it with a plate-measuring device.
If you are measuring dot areas with a reflection densitometer, use the 0% and 100% blocks for Dmin and Dmax measurements. Readings will depend on the platesetter/plate combination with which the Plate Control Strip is imaged and on processing variables.
For AM screening, you can use a screen ruling indicator to verify the screen rulings shown in the Plate Control Strip against those of the RIP and platesetter.
The Tone Scales section shows the requested screen and a reference screen.
On the upper row (Requested Screening), the RIP has generated a range of tones in the same way as it did for the rest of the plate. This area demonstrates the screening characteristics for the job. In the case of AM screening, it shows the angle, screen ruling, and dot shape. In the case of FM screening, it shows the tile pattern and feature size. The exact screening will vary according to this plate’s process color. If the job uses a tone calibration curve, the curve is also applied to the Tone Scale.
On the lower row (Reference screening), the KPCS file produces halftones in the same way as in the Highlight and Shadow Halftone Dots section, that is:
- The screens are produced within the KPCS file, not by the RIP. Any tone curves the RIP may be using do not affect these screens.
- Dots are written at the particular resolution specified in the file (that is, the device resolution).
- AM screening dots are written at 45 degrees, at the ruling specified in the file, although the exact number used may differ due to mathematical constraints.
- FM screening is done at the feature size specified in the file. The black tile pattern is used.
- Screen patterns are the same regardless of the plate’s process color.
The screened tints used in this section of the Plate Control Strip are not as sensitive to variables in the platemaking process as the pixel elements used in other sections. However, screened tints provide a familiar indicator.